Chapter 5, Problem 19P

Summary Introduction

To analyze:

The genetic linkage mapping for a large number of families identifies $\text{4\%}$ recombination between the genes for Rh blood type and elliptocytosis (Reference- problem $\text{18}$).

At Rh locus R controls Rh⁺, and r controls Rh^- blood types.

For elliptocytosis, allele E produces elliptocytosis while e is recessive and wild type.

Tom and Terri have elliptocytosis, and each is Rh⁺.

Tom’s mother has elliptocytosis and is Rh^- while his father is healthy and is Rh⁺.

Terri’s mother healthy and Rh^- whereas his father has elliptocytosis and is Rh⁺.

1. The probability of first child of Tom and Terri with Rh^- and suffering from elliptocytosis.

2. The probability that the child of Tom and Terri with Rh⁺ will suffer from elliptocytosis.

Introduction:

Elliptocytosisis an autosomal dominant inherited disease that causes genetic change in the genes responsible for maintenance of biconcave shape of RBC –red blood cells. These mutated genes convert the bi-concave shape to elliptical. Elliptocytosis causes reduced RBC production and accelerated RBC loss, premature destruction of RBC’s- hemolysis, etc. Elliptocytosis leads to hereditary anemia.

In autosomal dominant pattern, only single mutated allele is enough to cause the disease. The Autosomal dominant traits are passed from generations to generations, does not skip any generation, and both males and females are equally affected. Any one of the parents can transmit the mutated gene to the offspring.